File System Limits
| Block size: | 1 KB | 2 KB | 4 KB | 8 KB |
|---|---|---|---|---|
| max. file size: | 16 GB | 256 GB | 2 TB | 2 TB |
| max. filesystem size: | 4 TB | 8 TB | 16 TB | 32 TB |
The reason for some limits of ext2 are the file format of the data and the operating system's kernel. Mostly these factors will be determined once when the file system is built. They depend on the block size and the ratio of the number of blocks and inodes. In Linux the block size is limited by the architecture page size.
There are also some userspace programs that can't handle files larger than 2 GB.
The maximum file size is limited to min( ((b/4)3+(b/4)2+b/4+12)*b, 232*b ), due to the i_block (an array of EXT2_N_BLOCKS) and i_blocks (32-bit integer value) representing the number of b-byte "blocks" in the file.
The max number of sublevel-directories is 31998, due to the link count limit. Directory indexing is not available in ext2, so there are performance issues for directories with a large number of files (10,000+). The theoretical limit on the number of files in a directory is 1.3 × 1020, although this is not relevant for practical situations.
Note: In Linux 2.4 and earlier, block devices were limited to 2 TB, limiting the maximum size of a partition, regardless of block size.
Read more about this topic: Ext2
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